Mininet 系列实验（七）

• 实验内容

本实验在基于 Mininet 脚本的不同拓扑环境下使用 OpenDaylight 控制交换机行为。任务一：一台交换机两台主机，从1端口进入的数据流转发到 2 端口，从 2 端口进入的数据流转发到1端口；任务二：两台交换机两台主机，主机 0 连接交换机 0，主机 1 连接交换机 1，交换机 0 连接交换机 1，数据转发端口同任务一；任务三：与任务二类似，但是在创建 link 的时候，设置带宽、延迟以及丢包率。

• 参考

Mininet脚本实现控制交换机行为

• 实验环境

虚拟机: Oracle VM VirtualBox Ubuntu16.04LTS

• 实验步骤

任务一：一台交换机两台主机，实现从 1 端口进入的数据流转发到 2 端口，从 2 端口进入的数据流转发到 1 端口。

1.在~/mininet目录里新建文件 mymininet1.py

# cd mininet
# touch mininet
# vim mymininet1.py

脚本内容如下：

#!/usr/bin/python
from mininet.net import Mininet
from mininet.node import Node
from mininet.link import Link
from mininet.log import setLogLevel, info
from mininet.util import quietRun

from time import sleep

def scratchNet( cname='controller', cargs='-v ptcp:' ):
    "Create network from scratch using Open vSwitch."

    info( "*** Creating nodes\n" )
    controller = Node( 'c0', inNamespace=False )
    switch0 = Node( 's0', inNamespace=False )
    h0 = Node( 'h0' )
    h1 = Node( 'h1' )

    info( "*** Creating links\n" )
    Link( h0, switch0 )
    Link( h1, switch0 )

    info( "*** Configuring hosts\n" )
    h0.setIP( '192.168.123.1/24' )
    h1.setIP( '192.168.123.2/24' )
    info( str( h0 ) + '\n' )
    info( str( h1 ) + '\n' )

    info( "*** Starting network using Open vSwitch\n" )
    controller.cmd( cname + ' ' + cargs + '&' )
    switch0.cmd( 'ovs-vsctl del-br dp0' )
    switch0.cmd( 'ovs-vsctl add-br dp0' )

    for intf in switch0.intfs.values():
        print intf
        print switch0.cmd( 'ovs-vsctl add-port dp0 %s' % intf )
    switch0.cmd( 'ovs-vsctl set-controller dp0 tcp:10.0.2.15:6633' )
    # 这里的 IP 地址改为自己本机的，例如我的是10.0.2.15
    switch0.cmd( 'ovs-ofctl add-flow dp0 \"in_port=1 actions=output:2\"' )
    switch0.cmd( 'ovs-ofctl add-flow dp0 \"in_port=2 actions=output:1\"' )

    info( '*** Waiting for switch to connect to controller' )
    while 'is_connected' not in quietRun( 'ovs-vsctl show' ):
        sleep( 1 )
        info( '.' )
    info( '\n' )

    info( "*** Running test\n" )
    h0.cmdPrint( 'ping -c6 ' + h1.IP() )
    h1.cmdPrint( 'ping -c6 ' + h0.IP() )

    info( "*** Stopping network\n" )
    controller.cmd( 'kill %' + cname )
    switch0.cmd( 'ovs-vsctl del-br dp0' )
    switch0.deleteIntfs()
    info( '\n' )

if __name__ == '__main__':
    setLogLevel( 'info' )
    info( '*** Scratch network demo (kernel datapath)\n' )
    Mininet.init()
    scratchNet()

2.执行该脚本

# python mymininet1.py

任务二：两台交换机两台主机，主机 0 连接交换机 0，主机 1 连接交换机 1，交换机 0 连接交换机 1，数据转发端口要求同任务一。

1.在~/mininet目录里新建文件 mymininet2.py

# cd mininet
# touch mininet
# vim mymininet2.py

脚本内容如下：

#!/usr/bin/python
from mininet.net import Mininet
from mininet.node import Node
from mininet.link import Link
from mininet.log import setLogLevel, info
from mininet.util import quietRun

from time import sleep

def scratchNet( cname='controller', cargs='-v ptcp:' ):
    "Create network from scratch using Open vSwitch."

    info( "*** Creating nodes\n" )
    controller = Node( 'c0', inNamespace=False )
    switch0 = Node( 's0', inNamespace=False )
    switch1 = Node( 's1', inNamespace=False )
    h0 = Node( 'h0' )
    h1 = Node( 'h1' )

    info( "*** Creating links\n" )
    Link( h0, switch0 )
    Link( h1, switch1 )
    Link( switch0, switch1 )

    info( "*** Configuring hosts\n" )
    h0.setIP( '192.168.123.1/24' )
    h1.setIP( '192.168.123.2/24' )
    info( str( h0 ) + '\n' )
    info( str( h1 ) + '\n' )

    info( "*** Starting network using Open vSwitch\n" )
    controller.cmd( cname + ' ' + cargs + '&' )
    switch0.cmd( 'ovs-vsctl del-br dp0' )
    switch0.cmd( 'ovs-vsctl add-br dp0' )
    switch1.cmd( 'ovs-vsctl del-br dp1' )
    switch1.cmd( 'ovs-vsctl add-br dp1' )

    for intf in switch0.intfs.values():
        print intf
        print switch0.cmd( 'ovs-vsctl add-port dp0 %s' % intf )

    for intf in switch1.intfs.values():
        print intf
        print switch1.cmd( 'ovs-vsctl add-port dp1 %s' % intf )

    switch0.cmd( 'ovs-vsctl set-controller dp0 tcp:10.0.0.8:6633' )
    # 这里的 IP 地址改为自己本机的，例如我的是10.0.2.15
    switch1.cmd( 'ovs-vsctl set-controller dp1 tcp: 10.0.0.8:6633' )
    # 这里的 IP 地址改为自己本机的，例如我的是10.0.2.15
    switch0.cmd( 'ovs-ofctl add-flow dp0 \"in_port=1 actions=output:2\"' )
    switch0.cmd( 'ovs-ofctl add-flow dp0 \"in_port=2 actions=output:1\"' )
    switch1.cmd( 'ovs-ofctl add-flow dp1 \"in_port=1 actions=output:2\"' )
    switch1.cmd( 'ovs-ofctl add-flow dp1 \"in_port=2 actions=output:1\"' )

    info( '*** Waiting for switch to connect to controller' )
    while 'is_connected' not in quietRun( 'ovs-vsctl show' ):
        sleep( 1 )
        info( '.' )
    info( '\n' )
    print switch0.cmd( 'ovs-ofctl show dp0' )
    print switch1.cmd( 'ovs-ofctl show dp1' )

    info( "*** Running test\n" )
    h0.cmdPrint( 'ping -c3 ' + h1.IP() )
    h1.cmdPrint( 'ping -c3 ' + h0.IP() )

    info( "*** Stopping network\n" )
    controller.cmd( 'kill %' + cname )
    switch0.cmd( 'ovs-vsctl del-br dp0' )
    switch0.deleteIntfs()
    switch1.cmd( 'ovs-vsctl del-br dp1' )
    switch1.deleteIntfs()
    info( '\n' )

if __name__ == '__main__':
    setLogLevel( 'info' )
    info( '*** Scratch network demo (kernel datapath)\n' )
    Mininet.init()
    scratchNet()

2.执行该脚本

# python mymininet2.py

任务三：与任务二类似，但是在创建link的时候，设置带宽、延迟以及丢包率。

1.在~/mininet目录里新建文件 mymininet3.py

# cd mininet
# touch mininet
# vim mymininet3.py

脚本内容如下：

#!/usr/bin/python
from mininet.net import Mininet
from mininet.node import Node
from mininet.link import TCLink
from mininet.log import setLogLevel, info
from mininet.util import quietRun

from time import sleep

def scratchNet( cname='controller', cargs='-v ptcp:' ):
    "Create network from scratch using Open vSwitch."

    info( "*** Creating nodes\n" )
    controller = Node( 'c0', inNamespace=False )
    switch0 = Node( 's0', inNamespace=False )
    switch1 = Node( 's1', inNamespace=False )
    h0 = Node( 'h0' )
    h1 = Node( 'h1' )

    info( "*** Creating links\n" )

    linkopts0=dict(bw=10)
    linkopts1=dict(bw=10, delay='5ms', loss=10)
    TCLink( h0, switch0,**linkopts0)
    TCLink( h1, switch1,**linkopts0)
    TCLink( switch0, switch1,**linkopts1)

    info( "*** Configuring hosts\n" )
    h0.setIP( '192.168.123.1/24' )
    h1.setIP( '192.168.123.2/24' )
    info( str( h0 ) + '\n' )
    info( str( h1 ) + '\n' )

    info( "*** Starting network using Open vSwitch\n" )
    controller.cmd( cname + ' ' + cargs + '&' )
    switch0.cmd( 'ovs-vsctl del-br dp0' )
    switch0.cmd( 'ovs-vsctl add-br dp0' )
    switch1.cmd( 'ovs-vsctl del-br dp1' )
    switch1.cmd( 'ovs-vsctl add-br dp1' )

    for intf in switch0.intfs.values():
        print intf
        print switch0.cmd( 'ovs-vsctl add-port dp0 %s' % intf )

    for intf in switch1.intfs.values():
        print intf
        print switch1.cmd( 'ovs-vsctl add-port dp1 %s' % intf )

    switch0.cmd( 'ovs-vsctl set-controller dp0 tcp:10.0.0.8:6633' )
    # 这里的 IP 地址改为自己本机的，例如我的是10.0.2.15
    switch1.cmd( 'ovs-vsctl set-controller dp1 tcp: 10.0.0.8:6633' )
    # 这里的 IP 地址改为自己本机的，例如我的是10.0.2.15
    switch0.cmd( 'ovs-ofctl add-flow dp0 \"in_port=1 actions=output:2\"' )
    switch0.cmd( 'ovs-ofctl add-flow dp0 \"in_port=2 actions=output:1\"' )
    switch1.cmd( 'ovs-ofctl add-flow dp1 \"in_port=1 actions=output:2\"' )
    switch1.cmd( 'ovs-ofctl add-flow dp1 \"in_port=2 actions=output:1\"' )

    info( '*** Waiting for switch to connect to controller' )
    while 'is_connected' not in quietRun( 'ovs-vsctl show' ):
        sleep( 1 )
        info( '.' )
    info( '\n' )
    print switch0.cmd( 'ovs-ofctl show dp0' )
    print switch1.cmd( 'ovs-ofctl show dp1' )

    info( "*** Running test\n" )
    h0.cmdPrint( 'ping -c3 ' + h1.IP() )
    h1.cmdPrint( 'ping -c3 ' + h0.IP() )

    info( "*** Stopping network\n" )
    controller.cmd( 'kill %' + cname )
    switch0.cmd( 'ovs-vsctl del-br dp0' )
    switch0.deleteIntfs()
    switch1.cmd( 'ovs-vsctl del-br dp1' )
    switch1.deleteIntfs()
    info( '\n' )

if __name__ == '__main__':
    setLogLevel( 'info' )
    info( '*** Scratch network demo (kernel datapath)\n' )
    Mininet.init()
    scratchNet()

2.执行该脚本

# python mymininet3.py

• 总结

1. 实验过程中遇到的问题

• 一开始忘记修改代码中控制器的 IP 地址导致连接不上

2. 收获

• 熟悉 Mininet 自定义拓扑脚本的编写；
• 掌握使用「ovs-vsctl」命令直接控制 Open vSwitch。